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BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20250624T140000
DTEND;TZID=Europe/Paris:20250624T170000
DTSTAMP:20260418T220446
CREATED:20250606T134300Z
LAST-MODIFIED:20250623T102904Z
UID:14199-1750773600-1750784400@lmv.math.cnrs.fr
SUMMARY:AG : Ana-Maria Castravet (LMV) : Le 14ᵉ problème de Hilbert et de la géométrie birationnelle
DESCRIPTION:Résumé : Les contre-exemples de Mukai au 14ᵉ problème de Hilbert reposent sur une observation clé\, due à Nagata : les anneaux d’invariants pour certains groupes vectoriels peuvent être identifiés aux anneaux de Cox de certains éclatements d’espaces projectifs. L’anneau de Cox d’une variété encode une grande quantité d’informations sur la géométrie birationnelle de cette variété\, et on peut utiliser de la géométrie pour répondre à des questions concernant la finitude de la génération des anneaux d’invariants de Nagata. \nJe discuterai ces questions et expliquerai quel type de problèmes sont abordés en géométrie birationnelle\, ainsi que la manière dont on peut les traiter dans le cas des variétés algébriques qui sont des espaces de modules.
URL:https://lmv.math.cnrs.fr/evenenement/ag-ana-maria-castravet-lmv-2/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20250930T133000
DTEND;TZID=Europe/Paris:20250930T153000
DTSTAMP:20260418T220446
CREATED:20250604T140516Z
LAST-MODIFIED:20251003T113706Z
UID:14168-1759239000-1759246200@lmv.math.cnrs.fr
SUMMARY:AG : Tal Gottesman (Bochum) : Perspectives combinatoires autour des treillies Calabi--Yau fractionnaires
DESCRIPTION:Résumé : Les treillis Calabi–Yau fractionaires font l’objet de conjectures dues à Chapoton les liant à la géométrie symplectique. Les quelques examples qui corroborent ces conjectures étonnante mettent en scène des représentations associées à des antichaines dites Booléennes. Au cours de cet exposé\, je souhaite explorer les propriétés des ces antichaines. J’en profiterai pour présenter quelques dénombrements de ces objets obtenus par quatre étudiants au cours d’un stage à l’université de Bochum.
URL:https://lmv.math.cnrs.fr/evenenement/ag-tal-gottesman-bochum/
LOCATION:Bâtiment Fermat\, salle 4205
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20251007T133000
DTEND;TZID=Europe/Paris:20251007T143000
DTSTAMP:20260418T220446
CREATED:20250620T082501Z
LAST-MODIFIED:20251009T114319Z
UID:14228-1759843800-1759847400@lmv.math.cnrs.fr
SUMMARY:AG : Seda Albayrak (SFU\, Canada) : A refinement of Christol’s theorem for sparse algebraic power series
DESCRIPTION:Abstract: A famous result of Christol gives that a power series \(F(t)=\sum_{n\ge 0} f(n)t^n\) with coefficients in a finite field \(\mathbb{F}_q\) of characteristic \(p\) is algebraic over the field of rational functions in \(t\) if and only if there is a finite-state automaton accepting the base-\(p\) digits of \(n\) as input and giving \(f(n)\) as output for every \(n\ge 0\). An extension of Christol’s theorem\, giving a complete description of the algebraic closure of \(\mathbb{F}_q(t)\)\, was later given by Kedlaya. When one looks at the support of an algebraic power series\, that is the set of \(n\) for which \(f(n)\neq 0\)\, a well-known dichotomy for sets generated by finite-state automata shows that the support set is either sparse—with the number of \(n\le x\) for which \(f(n)\neq 0\) bounded by a polynomial in \(\log(x)\)—or it is reasonably large in the sense that the number of \(n\le x\) with \(f(n)\neq 0\) grows faster than \(x^{\alpha}\) for some positive \(\alpha\). The collection of algebraic power series with sparse supports forms a ring and we give a purely algebraic characterization of this ring in terms of Artin-Schreier extensions and we extend this to the context of Kedlaya’s work on generalized power series. (Joint work with Jason Bell).
URL:https://lmv.math.cnrs.fr/evenenement/ag-seda-albayrak-sfu-canada/
LOCATION:Bâtiment Fermat\, salle 4205
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20251014T133000
DTEND;TZID=Europe/Paris:20251014T143000
DTSTAMP:20260418T220446
CREATED:20251007T153917Z
LAST-MODIFIED:20251010T080344Z
UID:14422-1760448600-1760452200@lmv.math.cnrs.fr
SUMMARY:AG : John Lesieutre (Pennsylvania State University) : Volume near the pseudoeffective boundary
DESCRIPTION:Abstract: Suppose that X is a projective variety and that L is a line bundle on X. The volume of L is a measure of the asymptotic growth rate of the number of sections of tensor powers of L. After providing some background on this invariant\, I will explain some pathological behaviors of the volume function which have origins in the dynamics of birational automorphisms of a certain Calabi-Yau threefold X.
URL:https://lmv.math.cnrs.fr/evenenement/ag-john-lesieutre-pennsylvania-state-university/
LOCATION:Bâtiment Fermat\, salle 4205
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20251104T133000
DTEND;TZID=Europe/Paris:20251104T143000
DTSTAMP:20260418T220446
CREATED:20251016T084244Z
LAST-MODIFIED:20251107T103733Z
UID:14484-1762263000-1762266600@lmv.math.cnrs.fr
SUMMARY:AG : Lucas Pannier (LMV) : An effective proof of the p-curvature conjecture for first-order differential equations
DESCRIPTION:Abstract: In 1974\, Honda proved the p-curvature conjecture for order one differential equations with rational coefficients over a number field. He demonstrated that in this setting\, the p-curvature conjecture was equivalent to a theorem due to Kronecker\, providing a local-global criterion for the splitting of polynomials over the rational numbers. In 1985 the Chudnovskys published another proof of Honda’s theorem (and of Kronecker’s theorem) by means of Padé approximation and elementary number theory\, thus paving the way to an effective version of these results. Here\, by « effective » we mean that we wish to obtain an explicit finite bound on the number of p-curvatures to be computed in order to decide the algebraicity of the solution of the differential equation. \nIn this talk\, I will explain how to obtain such a bound\, and report on an implementation. \nThis is joint work with Florian Fürnsinn (University of Vienna).
URL:https://lmv.math.cnrs.fr/evenenement/ag-lucas-pannier-lmv/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20251118T133000
DTEND;TZID=Europe/Paris:20251118T143000
DTSTAMP:20260418T220446
CREATED:20250909T104118Z
LAST-MODIFIED:20251121T092217Z
UID:14343-1763472600-1763476200@lmv.math.cnrs.fr
SUMMARY:AG : Lucia Di Vizio (LMV) : Transcendances fonctionnelles
DESCRIPTION:  \nDans cet exposé\, je me focaliserai sur des questions d’indépendance algébrique des fonctions\, principalement du point de vue de la théorie de Galois des équations fonctionnelles. Je commenterai quelques résultats historiques (dus à Liouville\, Ostrowski\, Kolchin\, etc.) et montrerai leur influence jusqu’aux développements récents du domaine. L’objectif de l’exposé est de présenter une sélection forcément partielle de résultats du domaine à l’usage des non-spécialistes.
URL:https://lmv.math.cnrs.fr/evenenement/ag-lucia-di-vizio-lmv/
LOCATION:Bâtiment Fermat\, salle 4205
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20251125T080000
DTEND;TZID=Europe/Paris:20251125T170000
DTSTAMP:20260418T220446
CREATED:20250520T081903Z
LAST-MODIFIED:20251128T103551Z
UID:14100-1764057600-1764090000@lmv.math.cnrs.fr
SUMMARY:Journée du Séminaire différentiel au LMV
DESCRIPTION:Le Séminaire différentiel se tiendra au LMV toute la journée.  Cliquer ici pour plus d’informations. \nProgramme de la journée\n\n10:00 Accueil des participants \n10:30-11:30 — Jean-Pierre Ramis\nA new spectral theory: A complex analytic intrinsic theory with applications to the Connes-Moscovici spectrum\, which matches the zeros of zeta and to linear perturbations of black-holes\nI propose a new paradigm for the spectral theory of ODEs with analytic coefficients.\nThe classical approach is based on Hilbert spaces and linear operators (non necessarily bounded). My approach is based on analytic continuation\, in the complex domain\, and \n-summability\, otherwise speaking on wild monodromy.\nMy analytic spectra are intrinsic\, the boundary conditions are « contained in the equation ». I recently discovered that this last concept has been clearly formulated by Erwin Schr\ »odinger in a letter of december 27-th in relation with the hydrogen spectrum.\nThe analytic spectra are compatible with some « natural transformations » of ODEs as -homotopic transformations and gauge transformations. There are strong relations with special functions theory and the spectra appearing in natural sciences are in a lot of cases analytic spectra. There are numerous examples in quantum chemistry and in black holes theory.\nI will explain my understanding of the ideas of Schr\ »odinger on the hydrogen spectrum at the end of 1925. It is a first version of my notion of spectrum. After\, I will limit myself to the analytic spectra of the Confluent Heun Equations (CHE). The CHE are the rational linear second order ODEs admitting two regular singular points and an irregular singular point.\nThe analytic spectra are defined by the fact that the eigenfunctions are special solutions connecting local special solutions a two singular points. These local special solutions are\, by definition\,  eigenfunctions of the monodromy at a regular singular points and sum of an eigenfunction of the exponential torus (formal pure wave) at an irregular singular points.\nI will give some results on the generalised polynomial solutions of the CHE. Such solutions are defined by the fact that their logarithmic derivative is rational. Equivalently they connect special local solutions. One get them using the first step () of the Kovacic algorithm.\nI will present a new surprising result about the existence of algebraic one parameter families of CHEs admitting a basis of generalised polynomial solutions.\nI will give a new definition of the Connes-Moscovici spectrum\, which matches the zeros of zeta\, as an analytic bi-irregular spectrum and some consequences.\nI will explain how analytic spectra appear in the theory of perturbations of black-holes\, in relation with the Quasi-Normal-Modes (QNM) and with the algebraically special solutions. In this last case our results on the CHE admitting a basis of generalised polynomial solutions give a new light on the underlying physics.\nJoint works with Anne Duval\, Michè\`ele Loday-Richaud\, Emmanuel Paul\, Françoise Richard-Jung and Jean-Thomann.\n\n[Déjeuner] \n14:15-15:15 — Jacques Sauloy\,\nClassification analytique des équations aux q-différences et fibrés vectoriels holomorphes.\nSoit un complexe tel que . À tout module aux -différences analytique est associé un fibré vectoriel holomorphe sur la courbe elliptique associée (courbe de Tate). Pour les moduli fuchsiani\, ceci permet la classification analytique et même le calcul du groupe de Galois (Baranovsky-Ginzburg-Kontsevich). Pour les modules aux -différences analytiques quelconques\, on obtient la classification formelle (van der Put-Reversat-Atiyah). Pour avoir la classification analytique de modules quelconques (équations irrégulières)\, il est nécessaire (et suffisant) de prendre en compte la filtration canonique par les pentes du côté des modules ; et une notion de « filtration anti-HN » (HN pour Harder-Narasimhan) du côté des fibrés : c’est une variante d’un énoncé attribué à Ramis-Sauloy-Zhang par Kontsevich-Soibelman.\nIf (and only if) necessary and appropriate\, the talk will be given in English.\n\n15:15-16:15 — Jacques-Arthur Weil\nReduced Forms and Galois Groups of Differential or Functional Systems\nConsider a square matrix with entries in a differential field and the linear differential system . This system is said to be in reduced form when is in \, where \nis the Lie algebra of the differential Galois group. Putting a system into reduced form is a technique that has been developed over the last fifteen years to determine the Galois group (or information about transcendence) by several authors\, including the speaker. In this presentation\, I will explain the main techniques for determining a reduced form\, some recent progress\, and some ongoing questions. \n 
URL:https://lmv.math.cnrs.fr/evenenement/journee-du-seminaire-differentiel-au-lmv/
LOCATION:Bâtiment Fermat\, salle 4205
CATEGORIES:Séminaire AG,Séminaire différentiel
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20251202T133000
DTEND;TZID=Europe/Paris:20251202T143000
DTSTAMP:20260418T220446
CREATED:20251120T082550Z
LAST-MODIFIED:20251202T155049Z
UID:14601-1764682200-1764685800@lmv.math.cnrs.fr
SUMMARY:AG : Marta Benozzo (LMO) : Some hypersurface singularities over the p-adic integers
DESCRIPTION:Abstract: Even when trying to classify smooth varieties\, it is natural to stumble upon singular varieties. Recently\, there has been a lot of progress in the classification of varieties over fields of positive characteristics and over mixed characteristic DVR’s like \(\mathbb{Z}_p \). This has been possible partly thanks to the introduction of new notions of singularities related to Frobenius splittings and perfectoid methods\, respectively. Given a hypersurface in a projective space over the complex numbers\, we can measure how singular it is with an invariant called the « log canonical threshold ». Similarly\, in positive characteristic\, we can define the « F-pure threshold » and in mixed characteristic the « plus-pure threshold ». In this talk\, we will explore some examples of how to compute the plus-pure threshold and how this relates to the invariants in positive characteristic and in characteristic 0. This is based on joint work with V. Jagathese\, V. Pandey\, P. Ramírez-Moreno\, K. Schwede\, P. Sridhar.
URL:https://lmv.math.cnrs.fr/evenenement/ag-marta-benozzo-lmo/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20251209T133000
DTEND;TZID=Europe/Paris:20251209T143000
DTSTAMP:20260418T220446
CREATED:20251128T163226Z
LAST-MODIFIED:20251212T144219Z
UID:14637-1765287000-1765290600@lmv.math.cnrs.fr
SUMMARY:AG : Javier Fresan (Sorbonne Université) : Des moments de Bessel aux sommes de Kloosterman
DESCRIPTION:Résumé : Motivés par des calculs d’amplitudes de Feynman\, Broadhurst et Roberts ont proposé un programme pour comprendre l’origine motivique de certaines intégrales des fonctions de Bessel. Je présenterai des résultats obtenus en collaboration avec Claude Sabbah et Jeng-Daw Yu qui confirment une partie de leur conjectures. Au cœur de ce travail se trouve la construction d’une famille de motifs sur les nombres rationnels dont les périodes sont les intégrales de départ et dont la fonction L est obtenue à partir des puissances symétriques de sommes de Kloosterman sur les corps finis.
URL:https://lmv.math.cnrs.fr/evenenement/ag-javier-fresan-des-moments-de-bessel-aux-sommes-de-kloosterman/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260106T133000
DTEND;TZID=Europe/Paris:20260106T143000
DTSTAMP:20260418T220446
CREATED:20260102T080023Z
LAST-MODIFIED:20260105T091355Z
UID:14658-1767706200-1767709800@lmv.math.cnrs.fr
SUMMARY:AG : Manh Linh Nguyen (Jussieu) : Patching and the nine-term Mayer–Vietoris sequence for complexes of tori.
DESCRIPTION:We present the patching method\, a machinery developed by Harbater–Hartmann–Krashen and various other authors\, dedicated to the study of arithmetic of linear algebraic groups over function fields of curves over complete discretely valued fields such as ℚₚ(T). Then\, we present a new result in this direction\, which gives a 9-term exact sequence for Galois cohomology of 2-term complexes of tori in the patching setting. This relies on the notion of (co-)flasque resolutions of such complexes\, generalizing the previous work by Colliot-Thélène–Sansuc. As applications\, we show that patching holds for nonabelian second Galois cohomology of reductive groups with a smooth center\, as well as a weak local–global principle for this cohomology\nset. We also rediscover a local–global principle for indices of central simple algebras.
URL:https://lmv.math.cnrs.fr/evenenement/ag-manh-linh-nguyen-jussieu-patching-and-the-nine-term-mayer-vietoris-sequence-for-complexes-of-tori/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260113T133000
DTEND;TZID=Europe/Paris:20260113T143000
DTSTAMP:20260418T220446
CREATED:20251120T082820Z
LAST-MODIFIED:20260116T083300Z
UID:14603-1768311000-1768314600@lmv.math.cnrs.fr
SUMMARY:AG : Sorina Ionica (LMV) : Construction de courbes hyperelliptiques de genre 3 et multiplication complexe
DESCRIPTION:Dans cet exposé\, nous nous intéressons au problème du calcul effectif de courbes hyperelliptiques de petit genre définies sur le corps des complexes\, dont la jacobienne est simple et admet une multiplication complexe. En genre 1 et 2\, la théorie de la multiplication complexe fournit une réponse naturelle\, puisque toutes les variétés abéliennes principalement polarisées (v.a.p.p.) simples de dimension 1 et 2 sont isomorphes aux jacobiennes de courbes hyperelliptiques. En genre 3\, la situation est plus complexe et donc plus intéressante. À isomorphisme près\, toute v.a.p.p. de dimension 3 est la jacobienne d’une courbe\, laquelle est soit hyperelliptique\, soit une quartique plane. De plus\, le cas générique est celui d’une quartique plane. Je montrerai les résultats obtenus concernant la construction de jacobiennes de courbes hyperelliptiques de genre 3 à multiplication complexe\, et je présenterai quelques questions ouvertes relatives au calcul de leurs invariants.
URL:https://lmv.math.cnrs.fr/evenenement/ag-sorina-ionica-lmv/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260120T140000
DTEND;TZID=Europe/Paris:20260120T150000
DTSTAMP:20260418T220446
CREATED:20251128T163433Z
LAST-MODIFIED:20260123T131759Z
UID:14639-1768917600-1768921200@lmv.math.cnrs.fr
SUMMARY:AG : Gérard Freixas (CMLS) : Sur l’isomorphisme de Deligne-Riemann-Roch
DESCRIPTION:Résumé: Dans une lettre à Quillen datant des années 80\, Deligne a proposé un programme conjectural dont le but ultime est de relever la formule de Grothendieck-Riemann-Roch en degré 1\, en un isomorphisme de fibrés en droites\, avec une dépendance fonctorielle dans les données. Basé sur les travaux de Mumford sur les espaces de modules de courbes\, Deligne a traité le cas de dimension relative 1. Dans cet exposé\, je donnerai un aperçu du programme de Deligne\, et je présenterai un travail avec Dennis Eriksson\, dans lequel nous établissons un isomorphisme de Deligne-Riemann-Roch en général.
URL:https://lmv.math.cnrs.fr/evenenement/ag-gerard-freixas-cmls/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260127T133000
DTEND;TZID=Europe/Paris:20260127T143000
DTSTAMP:20260418T220446
CREATED:20260121T212242Z
LAST-MODIFIED:20260130T081503Z
UID:14720-1769520600-1769524200@lmv.math.cnrs.fr
SUMMARY:AG : Quang Khai Nguyen : Université Lyon 1 : Generating series of degree sequences in algebraic dynamics
DESCRIPTION:In algebraic dynamics\, we wish to understand the integer sequence given by the degrees of iterates of a dominant rational self-map. Typical examples include the Fibonacci sequence and other linear recurrence sequences\, though not all such degree sequences satisfy a finite recurrence. Their growth is captured by the dynamical degree\, an invariant governing the topological and arithmetic complexity of the dynamical system. I will present algebraic and analytic results concerning the generating series of these sequences in the toric setting\, including an affirmative answer to Jason Bell’s question on the transcendence of the reduction of these series modulo primes.
URL:https://lmv.math.cnrs.fr/evenenement/quang-khai-nguyen-universite-lyon-1-generating-series-of-degree-sequences-in-algebraic-dynamics/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260203T133000
DTEND;TZID=Europe/Paris:20260203T143000
DTSTAMP:20260418T220446
CREATED:20260125T161030Z
LAST-MODIFIED:20260203T160622Z
UID:14741-1770125400-1770129000@lmv.math.cnrs.fr
SUMMARY:AG : Mikhail Zaitsev : Proof of the KKLS conjecture on the mean value of the gl-weight system (HSE\, IHES)
DESCRIPTION:In my talk\, I will introduce several sets of central elements in the universal enveloping algebra U(gl_N) and explain the relationships between them using average value of the gl-weight system as an example. As a consequence\, we obtain a proof of the M.Kazarian\, E.Krasilnikov\, S.Lando\, and M.Shapiro conjecture that the mean value of the gl-weight system is a tau function of the KP hierarchy.
URL:https://lmv.math.cnrs.fr/evenenement/mikhail-zaitsev-proof-of-the-kkls-conjecture-on-the-mean-value-of-the-gl-weight-system/
LOCATION:Bâtiment Fermat\, salle 4205
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260210T133000
DTEND;TZID=Europe/Paris:20260210T143000
DTSTAMP:20260418T220446
CREATED:20260205T093532Z
LAST-MODIFIED:20260213T083519Z
UID:14774-1770730200-1770733800@lmv.math.cnrs.fr
SUMMARY:AG : Florian Fürnsinn (Université de Vienne) : Galois Groups of D-finite Series modulo Primes
DESCRIPTION:Abstract: A D-finite series is a power series over the rational numbers that satisfies a linear differential equation with polynomial coefficients. Reducing a D-finite series modulo a prime number one often obtains an algebraic power series in positive characteristic. For diagonals of multivariate rational functions this was observed by Furstenberg in 1967\, and for hypergeometric functions this can be deduced from results by Christol\, and was made precise in recent work by Vargas-Montoya. In these cases\, one can consider the Galois group of the reduction over the field of rational functions. \nIn this talk\, I will showcase many examples of D-finite series of different nature for which we are (almost) able to compute said Galois groups for almost all prime numbers for which they are defined. Then\, I will collect these observations to raise questions on the general behavior of these groups: Is there some uniformity of the Galois groups with respect to the prime number\, and does there exist an object in characteristic zero governing their behavior\, like the differential Galois group of the minimal equation for the series? Much like the Grothendieck p-curvature conjecture\, we are looking for a local-global principle\, but we are concerned with only a single solution of a differential equation\, instead of a full basis. \nThis talk is based on joint work with X. Caruso and D. Vargas-Montoya.
URL:https://lmv.math.cnrs.fr/evenenement/ag-florian-furnsinn-universite-de-vienne/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260217T133000
DTEND;TZID=Europe/Paris:20260217T150000
DTSTAMP:20260418T220446
CREATED:20260122T134356Z
LAST-MODIFIED:20260220T084240Z
UID:14729-1771335000-1771340400@lmv.math.cnrs.fr
SUMMARY:AG : Pierre-Guy Plamondon (LMV) : Représentations\, amas et espaces de configurations
DESCRIPTION:Résumé : Je vais expliquer comment les algèbres amassées\, puis la théorie des représentations\, peuvent servir pour réaliser certains espaces de configurations.  Je me concentrerai sur l’espace \(M_{0\,n}\) des configurations de n points distincts sur la droite projective\, qui est lié à la théorie des représentations d’un carquois de type Dynkin \(A_{n-3}\). Si le temps le permet\, je parlerai de résultats obtenus dans cette direction avec Arkani-Hamed\, Frost\, Salvatori et Thomas.
URL:https://lmv.math.cnrs.fr/evenenement/ag-pierre-guy-plamondon-lmv-2/
CATEGORIES:Séminaire AG
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260317T133000
DTEND;TZID=Europe/Paris:20260317T143000
DTSTAMP:20260418T220446
CREATED:20260121T212551Z
LAST-MODIFIED:20260319T110212Z
UID:14722-1773754200-1773757800@lmv.math.cnrs.fr
SUMMARY:AG : Trung Nghiem : Université Lyon 1 : Une construction effective des variétés de Calabi–Yau asymptotiquement coniques
DESCRIPTION:Une métrique asymptotiquement conique de Calabi–Yau est une métrique kählérienne à courbure de Ricci nulle\, dont l’allure à l’infini ressemble à un cône de Calabi–Yau. Un travail récent de Conlon–Hein montre qu’une variété AC de Calabi–Yau à cône asymptotique donné est obtenue soit par déformation\, soit par désingularisation crépante du cône. En fonction de la métrique sur le cône\, la variété AC est dite quasi-régulière ou irrégulière. Les exemples du dernier sont notamment rares dans la littérature et relativement beaucoup moins faciles à construire que les exemples quasi-réguliers. Dans mon exposé\, je vais présenter une stratégie effective pour construire des variétés non-compactes de Calabi–Yau irrégulières via la théorie d’Altmann sur les déformations des cônes toriques de Calabi–Yau. Il s’agit d’un travail en commun avec Ronan J. Conlon (University of Texas\, Dallas).
URL:https://lmv.math.cnrs.fr/evenenement/trung-nghiem-universite-lyon-1/
CATEGORIES:Séminaire AG
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DTSTART;TZID=Europe/Paris:20260324T133000
DTEND;TZID=Europe/Paris:20260324T143000
DTSTAMP:20260418T220446
CREATED:20260315T174427Z
LAST-MODIFIED:20260327T131156Z
UID:14871-1774359000-1774362600@lmv.math.cnrs.fr
SUMMARY:AG : Lucas Gerth (Jussieu) : Moduli spaces of analytic p-divisible groups.
DESCRIPTION:Abstract: We prove a classification of families of analytic p-divisible groups on adic spaces S over Qp in terms of Hodge–Tate triples on S\, generalizing a theorem of Fargues. From this\, for S a perfectoid space\, we construct an analytic Dieudonné theory with values in mixed characteristic Shtukas over the Fargues–Fontaine disc. As applications\, we realize the local Shimura varieties of EL and PEL type of Scholze–Weinstein as moduli spaces of analytic p-divisible groups with framed universal cover\, and we reinterpret the Hodge–Tate period map of Scholze in terms of topologically p-torsion subgroups of abelian varieties.
URL:https://lmv.math.cnrs.fr/evenenement/ag-lucas-gerth-jussieu/
CATEGORIES:Séminaire AG
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BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260414T133000
DTEND;TZID=Europe/Paris:20260414T143000
DTSTAMP:20260418T220446
CREATED:20260402T130306Z
LAST-MODIFIED:20260417T082256Z
UID:14895-1776173400-1776177000@lmv.math.cnrs.fr
SUMMARY:AG : Alexander Stadler (University of Vienna) : Combinatorics of Extended Multi-Segments
DESCRIPTION:Abstract: Let F be a p-adic field. We consider representations of Arthur type of a classical group G over F. By use of the Endoscopic Classification\, Moeglin gave an explicit way to construct Arthur packets when G is a symplectic or special orthogonal group. Further analysis by Xu and Atobe developed the notion of Extended Multi-Segments\, which parametrise certain Arthur packets. We review the definition\, the construction of these representations in terms of Langlands data and consider some combinatorial problems that arise in this context.
URL:https://lmv.math.cnrs.fr/evenenement/ag-alexander-stadler/
CATEGORIES:Séminaire AG
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DTSTART;TZID=Europe/Paris:20260519T133000
DTEND;TZID=Europe/Paris:20260519T143000
DTSTAMP:20260418T220446
CREATED:20260302T163943Z
LAST-MODIFIED:20260302T163943Z
UID:14829-1779197400-1779201000@lmv.math.cnrs.fr
SUMMARY:AG : Bernhard Keller (IMJ-PRG)
DESCRIPTION:
URL:https://lmv.math.cnrs.fr/evenenement/ag-bernhard-keller-imj-prg/
CATEGORIES:Séminaire AG
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BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260526T133000
DTEND;TZID=Europe/Paris:20260526T143000
DTSTAMP:20260418T220446
CREATED:20260305T161023Z
LAST-MODIFIED:20260305T161023Z
UID:14833-1779802200-1779805800@lmv.math.cnrs.fr
SUMMARY:AG : Sophie Morier-Genoud (Université de Reims)
DESCRIPTION:
URL:https://lmv.math.cnrs.fr/evenenement/ag-sophie-morier-genoud-universite-de-reims/
CATEGORIES:Séminaire AG
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BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260609T133000
DTEND;TZID=Europe/Paris:20260609T143000
DTSTAMP:20260418T220446
CREATED:20260304T131807Z
LAST-MODIFIED:20260304T131807Z
UID:14831-1781011800-1781015400@lmv.math.cnrs.fr
SUMMARY:AG : Baptiste Rognerud (IMJ-PRG)
DESCRIPTION:
URL:https://lmv.math.cnrs.fr/evenenement/ag-baptiste-rognerud-imj-prg-2/
CATEGORIES:Séminaire AG
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BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20260616T133000
DTEND;TZID=Europe/Paris:20260616T143000
DTSTAMP:20260418T220446
CREATED:20260403T085232Z
LAST-MODIFIED:20260403T085232Z
UID:14899-1781616600-1781620200@lmv.math.cnrs.fr
SUMMARY:AG : Jeremy Lovejoy (CNRS\, Université Paris Cité)
DESCRIPTION:
URL:https://lmv.math.cnrs.fr/evenenement/ag-jeremy-lovejoy-cnrs-universite-paris-cite/
CATEGORIES:Séminaire AG
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